| Mills & Jellicoe Limited | Hospitality | 2021 |
| Mills & Sons (Southwold) Limited | Wholesale & retail | 2013 |
| MLP Media Consultancy Ltd | Professional & scientific | 2025 |
| Monetize Value Limited | Professional & scientific | 2025 |
| Morley a Property Ltd | Real estate | 2025 |
| Move Mount Shoot Limited | Other services | 1990 |
| Mrwcf Electrical Limited | Construction | 2009 |
| Murray Graham Limited | Professional & scientific | 2019 |
| Musker Mcintyre Auctions Ltd | Real estate | 2010 |
| Naas Networks Limited | Information & communication | 2016 |
| Natural Building Systems Limited | Construction | 2019 |
| Nature's Ingredients Limited | Wholesale & retail | 2015 |
| NCE Drilling Consultants Limited | Mining & quarrying | 2015 |
| Neat Spaces Ltd | Administrative & support | 2026 |
| Nebelli Limited | Information & communication | 2019 |
| Neil Page (Lowestoft) Limited | Professional & scientific | 2006 |
| New CUT Arts | Arts & recreation | 2007 |
| New Moon Holistics Ltd | Wholesale & retail | 2023 |
| Nicholson Fabrication Limited | Manufacturing | 2019 |
| Nick Haward (Southwold) Limited | Construction | 2001 |
| Nick Haward Building Design & Management Services Ltd | Construction | 2014 |
| Nicolae Bigligiu Ltd | Transport & logistics | 2015 |
| NJ Designs (Suffolk) Ltd | Manufacturing | 2020 |
| NK Holton Developments Limited | Real estate | 2023 |
| NMT Health Physics Ltd | Other services | 2019 |
| Noble Prawn Ltd | Hospitality | 2021 |
| Noor Pictures Limited | Information & communication | 2009 |
| Norfolk & Suffolk Waste Limited | Water & waste | 2024 |
| Normans Transport UK Limited | Transport & logistics | 2010 |
| Northgate Marine Limited | Manufacturing | 2009 |
| Novabright Training Ltd | Education | 2018 |
| O B Y Management Limited | Households | 1999 |
| Oak View Developments (Suffolk) Ltd | Construction | 2021 |
| OCE Systems Limited | Water & waste | 2004 |
| Olivers Property Agents Limited | Real estate | 2010 |
| Opulence Firewood Limited | Wholesale & retail | 2024 |
| Opulence Limited | Wholesale & retail | 2007 |
| Orchard Frames Limited | Wholesale & retail | 2005 |
| Overton Surveying Limited | Construction | 2023 |
| P C Plumbing & Heating (East Anglia) Limited | Construction | 2018 |
| P Holmes Construction Limited | Construction | 2024 |
| P.A. Medical Solutions Limited | Administrative & support | 2011 |
| Parkace Ltd | Transport & logistics | 2026 |
| Pathfinder Development Consultants Limited | Professional & scientific | 2013 |
| Pearce and Kemp Limited | Construction | 1972 |
| Pearl Global Yacht Services Limited | Administrative & support | 2015 |
| Pearls Boutique Limited | Wholesale & retail | 2022 |
| Pearls by the Sea Limited | Wholesale & retail | 2023 |
| Pepperell's Meats Ltd | Wholesale & retail | 2002 |
| Perdix Publishing Limited | Professional & scientific | 1998 |
| Pharm-Binz Limited | Professional & scientific | 2008 |
| Pizza Street EN Limited | Hospitality | 2025 |
| PJ Crockford Construction Ltd | Construction | 2004 |
| PJN Motor Engineering Limited | Wholesale & retail | 2003 |
| PLANS4ME Limited | Professional & scientific | 2024 |
| Plough on Ltd | Hospitality | 2018 |
| PMD Garage Equipment Limited | Manufacturing | 2020 |
| Pond Lane Management Limited | Real estate | 2006 |
| Porters Farms (Walpole) Limited | Agriculture & fishing | 1964 |
| Posh Tubs Hot TUB Hire Ltd | Administrative & support | 2017 |
| Prima LUX Limited | Hospitality | 2021 |
| Prime Universal Ltd | Wholesale & retail | 1998 |
| Pro Golf Wizard Ltd | Information & communication | 2015 |
| Pro-Dat Applications Limited | Information & communication | 2014 |
| Project Management (UK) Limited | Construction | 2013 |
| Promgmt Ltd | Professional & scientific | 2019 |
| Property Special Purpose Vehicle (a) Limited | Real estate | 2022 |
| Property Special Purpose Vehicle (B) Limited | Real estate | 2022 |
| Psycho Dynamics Ltd | Health & social care | 2002 |
| Purple Dragon (EA) Limited | Financial services | 2026 |
| Purple Pumpkin Creative Studio Ltd | Arts & recreation | 2019 |
| QMD (UK) Ltd | Construction | 2001 |
| Quantum Progress Limited | Information & communication | 2007 |
| Quarto Development Consultants Limited | Professional & scientific | 2012 |
| Quincrete Limited | Financial services | 1965 |
| R & a Clarke Limited | Construction | 2020 |
| R & a Neale Associates Limited | Professional & scientific | 2019 |
| R & R Clarke Limited | Other services | 2023 |
| R E Barnes Limited | Administrative & support | 2002 |
| R.G.Wright & Sons Limited | Agriculture & fishing | 1963 |
| Raffee Competitions Ltd | Wholesale & retail | 2024 |
| Railings Property Limited | Real estate | 2019 |
| Rampart Road Management Company Limited | Real estate | 2005 |
| RCT Property Development Limited | Real estate | 2020 |
| Ready Record Limited | Administrative & support | 2008 |
| Real Good Holding Ltd | Financial services | 2022 |
| Rebecca Regis Property Search Limited | Real estate | 2022 |
| Rectory Green (Halesworth) Limited | Households | 1994 |
| Red Dune Limited | Information & communication | 2000 |
| Reeders of Halesworth Limited | Wholesale & retail | 2022 |
| Rekha Photography Ltd. | Professional & scientific | 2019 |
| Renover Property Ltd | Construction | 2026 |
| Retreat Holidays Limited | Hospitality | 2023 |
| RG Events Ltd | Hospitality | 2020 |
| Richards Coaching and Consulting Limited | Education | 2021 |
| RL White Property Ltd | Real estate | 2025 |
| Roger Hardy Limited | Arts & recreation | 2018 |
| Rrago Jack Leasing Ltd | Administrative & support | 2025 |
| Rrago Jack Recruitment Limited | Administrative & support | 2025 |
| Rumburgh Common Limited | Agriculture & fishing | 2014 |